JPH1015640A - Mold for electromagnetic casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high magnetic field transmission type and high energy efficiency type electromagnetic casting mold having small energy loss by arranging and integrating a conducting part and a high resistance part in the peripheral direction, forming a cooling chamber so as to surround these parts and incorporating the electromagnetic coil in the inner part of the cooling chamber. SOLUTION: At the time of conducting current to an electromagnetic coil 20, the magnetic field generated by this current is directly transmitted to the high resistance part 30 and impressed to molten steel 13 in the inner part. Further, the magnetic field is indirectly transmitted to the molten steel 13 through the conducting part 2 composed of a copper alloy. Then, magnetic repulsive force is developed between the molten steel 13 and the mold wall 12 by the magnetic field directly transmitting the high resistance part 30 and the magnetic field indirectly transmitted through the conducting part 28, and thus, contact pressure between the molten steel 13 and the mold wall 12 is reduced. By this constitution, the magnetic field supplied through the magnetic coil can efficiently be acted to the molten steel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic casting mold, and more particularly, to a high magnetic field transmission type and high energy efficiency type electromagnetic casting mold.

[0002]

2. Description of the Related Art In a continuous casting process of aluminum, electromagnetic casting utilizing magnetic pressure generated by an electromagnetic field is known as one of methods for improving the surface properties of a slab. This is a method of solidifying while holding molten aluminum by magnetic pressure instead of using a mold, and has a great effect in preventing defects caused by contact between the mold and the surface of the slab.

[0003] On the other hand, in the field of iron and steel, it is difficult to completely support molten steel by magnetic pressure when considered on an industrial level due to the high density of steel and the high casting speed. A mold for molding the resin into a predetermined shape is essential.

Conventionally, a split type water-cooled mold as shown in FIG. 5 has been used as a mold for this purpose, that is, as a mold for electromagnetic casting. In FIG. 5, reference numeral 200 denotes a split type water-cooled mold, in which a plurality of divided segments 202 made of copper or copper alloy are circumferentially connected via slits, and an insulating material 204 such as mica is provided in the slits. Each segment 202 is electrically insulated by being interposed.

[0005] Inside each segment 202, a cooling chamber 206 for passing cooling water is formed, and outside the cylindrical mold wall comprising each segment 202 and insulating material 204, the mold wall is provided. An electromagnetic coil 208 is provided so as to surround the body.

In this mold 200 for electromagnetic casting, a magnetic field generated by a current flowing through the electromagnetic coil 208 is applied to the molten steel 210 inside through the mold 200, and generated between the mold 200 and the molten steel 210. Due to the magnetic repulsion, the contact pressure between molten steel 210 and mold 200 is reduced. Thereby, casting can be performed smoothly.

In addition, in the case of the electromagnetic casting, in addition to the action of reducing the contact pressure, due to a change in the meniscus shape of the molten steel 210 during casting, specifically, the surface of the molten steel 210 becomes a raised shape. The mold powder smoothly flows between the molten steel 210 and the mold 200, and as a result, the molten steel 210
When continuous casting is performed, it is possible to reduce or eliminate the undulating shape generated on the surface of the slab, and to obtain advantages such as obtaining a slab having good surface properties.

In this electromagnetic casting, the magnetic field acting (applied) on molten steel 210 inside mold 200 is arranged in a slit between segments 202 and 202 in the mold wall, more specifically, in the slit. A magnetic field that penetrates through the insulating material 204 and acts inside, a magnetic field that penetrates into the inside of the mold 200 from above and below, and an eddy current induced on the surface of the segment 202 by a magnetic field created by a coil current indirectly enters the inside of the mold A transmitted magnetic field and the like can be mentioned.

[0009]

The conventional mold 2
In the case of No. 00, the following problems are inherent due to the fact that the mold wall is divided into the respective segments 202 and the cooling chambers 206 are formed inside the respective segments 202.

As described above, the magnetic field transmitted indirectly through the mold 200 increases as the thickness of the mold wall increases and the shielding effect of the mold wall increases. By being located far away from 210, it is necessarily weaker.

In the case of the conventional mold 200, since it is necessary to form the cooling chamber 206 inside each segment 202, specifically, it is necessary to secure the cooling chamber 206 having a predetermined space volume. In addition, at that time, the thickness of the mold 202 is increased from the viewpoint of securing the thickness of the segment 202 to a certain thickness or more and further securing workability. As a result, the mold 200 and the molten steel 210 In order to generate the desired magnetic repulsion during
In such a case, it is necessary to supply a large current to the power supply, resulting in poor energy efficiency.

That is, in the case of the conventional mold 200, the permeability of the magnetic field is low, and the energy applied from the electromagnetic coil 208 is largely consumed by the eddy current and Joule heat generated in the mold 200, and the magnetic repulsive force of the molten steel 210 There was a problem that was not communicated effectively.

In addition, in the case of the above-mentioned conventional split-type water-cooled mold 200, the cooling action on the molten steel 210 tends to be uneven, and since the mold wall is divided into the segments 202, the strength of the mold itself is uneven. The problem of becoming weaker was also inherent. In addition, since the cooling chamber 206 must be formed in each of the segments 202, there is a problem that processing is also difficult.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high magnetic field transmission type and high energy efficiency type electromagnetic casting mold in order to solve such a problem. In order to achieve this object, an electromagnetic casting mold according to the invention of the present application comprises (a) a conductive part made of a conductive metal material and a metal oxide, and has a high resistance to the conductive part. And (b) formed around the outer peripheral side of the mold wall so as to surround the mold wall. A cooling chamber for passing a cooling medium, and (c) an electromagnetic coil which is housed in the cooling chamber so as to surround the mold wall (claim 1).

According to another aspect of the present invention, there is provided an electromagnetic casting mold according to claim 1, wherein the conductive portion is made of copper or a copper alloy, and the high-resistance portion is a metal oxide powder and a constituent material of the conductive portion. And a conductive body and a high-resistance part are integrated by sintering (claim 2).

[0016]

As described above, according to the present invention, a conductive member made of a conductive metal material and a high-resistance portion containing a metal oxide are circumferentially arranged and integrated to form a mold wall. A cooling chamber is formed so as to surround the cooling chamber, and an electromagnetic coil is accommodated in the cooling chamber. That is, the electromagnetic coil is built in the cooling chamber and integrated with a mold.

As described above, in the case of the conventional mold, a slit is formed between each segment, and in the slit, strictly speaking, an insulating material arranged in the slit directly transmits a magnetic field generated by the coil into the inside of the mold. In addition, the segments can be electrically insulated in the circumferential direction by the insulating material, and the shielding effect of the mold by the magnetic field can be suppressed.

On the other hand, on the other hand, since it is necessary to divide the segment into the segments and to interpose the insulating material at the divided portion, it is necessary to form a cooling chamber inside each of the segments. This has caused the magnetic field permeability of the mold to decrease and the energy efficiency to deteriorate.

However, in the present invention, since the mold wall is formed as an integral structure and the cooling chamber is formed outside the mold wall so as to surround the mold wall, the thickness of the mold wall is made as thin as possible. It is possible to suppress the magnetic field shielding effect by the mold wall as small as possible while ensuring the direct transmission of the magnetic field in the high resistance portion containing the metal oxide.

In addition, in the present invention, since the electromagnetic coil is accommodated inside the cooling chamber, the electromagnetic coil can be arranged at a position close to the molten metal inside the mold, and the electromagnetic coil is generated by the electromagnetic coil. The applied magnetic field can be efficiently applied to the inside of the mold, that is, the molten metal.

In the present invention, a continuous cooling chamber can be formed around the mold wall, whereby the effect of uniformizing the cooling action on the molten metal can be obtained, and the mold wall can be integrated with the integrated structure. As a result, it is possible to increase the structural strength of the mold wall, and it is not necessary to process and form a cooling chamber inside the mold wall unlike a conventional mold. There is an advantage that the final processing is easy.

In the present invention, since the electromagnetic coil is housed in the cooling chamber, the cooling medium in the cooling chamber can cool the electromagnetic coil itself together with cooling the mold wall. Is obtained.

In the present invention, the conductive portion is made of copper or a copper alloy, and the high-resistance portion is made of a sintered body of a powder containing a metal oxide powder and a copper or copper alloy powder; The conductive portion and the high-resistance portion can be integrated by sintering (claim 2). This makes it possible to easily obtain a strong mold wall having an integral structure including the conductive portion and the high-resistance portion.

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; In FIG. 1, reference numeral 10 denotes an electromagnetic casting mold of the present embodiment for continuously casting a slab having a round cross-section, and reference numeral 12 denotes a cylindrical shape for casting molten steel 13 into a slab having a round cross-section. It is a mold wall.

An outer cover 14 has an inward flange-shaped mold retainer 16 at the upper end. A circumferentially continuous cooling chamber 18 is formed between the mold wall 12 and the outer cover 14 so as to surround the mold wall 12. The electromagnetic coil 20 is arranged in a form surrounding. Here, the surface of the electromagnetic coil 20 is coated with an insulating and waterproof coating. Here, 22 is a dip tube, 24 is a solidified shell, 26
Is a mold powder.

FIG. 2 is an enlarged cross-sectional view of the mold wall 12. In FIG. 2, reference numeral 28 denotes a highly conductive conductive portion made of a copper alloy, and reference numeral 30 denotes a metal oxide (in this example, a metal oxide). This is a substantially insulating high-resistance portion made of a ceramics-dispersed copper alloy obtained by dispersing alumina particles) in a copper alloy of the same type as the conductive portion 28.

The high-resistance portion 30 made of a composite material of a copper alloy and ceramics is a portion having the same function as a slit or an insulating material layer in a conventional split type water-cooled mold, The width is narrow in the circumferential direction, and electrically insulates the conductive portions 28 substantially in the circumferential direction.

FIG. 3 shows an example of a method of manufacturing the mold wall 12. In the figure, reference numeral 32 denotes a copper alloy plate;
Reference numeral 4 denotes a powder raw material containing a copper alloy powder of the same type as the copper alloy plate 32 and a ceramic powder such as alumina.

In the method shown in FIG. 3, these copper alloy plates 32
And the powder raw material 34 are charged into the inside of the HIP can 36, the powder raw material 34 is filled in the gap between the copper alloy plates 32, 32, and the HIP can 36 is closed with the lid closed. To process. Then, the powder raw material 34 is sintered by the HIP process, and is simultaneously integrated with the copper alloy plate 32.

Next, the cylindrical body 3 obtained by the HIP process
The central portion of 8 is hollowed out to obtain a cylindrical mold wall 12. In the mold wall body 12 thus manufactured,
The sintering of the powder raw material 34 forms the high-resistance portion 30 made of the ceramic dispersed copper alloy, and at the same time, the high-resistance portion 30 made of the sintered body and the conductive portion 28 made of the copper alloy.
Are sintered and integrated well.

In the case of the electromagnetic casting mold 10 of this embodiment, when a current is applied to the electromagnetic coil 20, the magnetic field generated by the current is directly transmitted through the high resistance portion 30 and applied to the molten steel 13 inside. At the same time, it is indirectly transmitted to the molten steel 13 via the conductive portion 28 made of a copper alloy. The molten steel 13 and the mold wall 12 are formed by the magnetic field directly transmitted through the high resistance portion 30 and the magnetic field transmitted indirectly through the conductive portion 28.
And a magnetic repulsive force is generated between the molten steel 13 and the contact pressure between the molten steel 13 and the mold wall 12.

Further, the molten steel 13
The surface shape, that is, the meniscus shape is raised upward, and the mold powder 26 smoothly flows between the molten steel 13 and the mold wall 12, and the lubrication at the time of casting the molten steel 13 is performed by the mold powder 26. Performs well.

In the mold 10 for electromagnetic casting of the present embodiment, a conductive portion 28 made of a copper alloy and a high-resistance portion 30 containing a metal oxide are arranged in the circumferential direction, and they are integrated to form the mold wall 12. In addition, a cooling chamber 18 is formed so as to surround the cooling chamber 18 and an electromagnetic coil 20 is accommodated therein. In the mold 10 of the present embodiment, the thickness of the mold wall 12 is made as small as possible. In addition, it is possible to suppress the action of shielding the magnetic field by the mold wall 12 as small as possible while ensuring the direct transmission of the magnetic field in the high-resistance portion 30.

Further, since the electromagnetic coil 20 is housed inside the cooling chamber 18, the electromagnetic coil 20 can be arranged at a position close to the molten steel 13 inside the mold, and the magnetic field generated by the electromagnetic coil 20 is reduced. It can be made to act on the molten steel 13 efficiently.

Further, in the case of the mold 10 of this embodiment, the structural strength of the mold wall 12 can be increased, and the cooling chamber 18
Is formed continuously around the mold wall 12,
The cooling action on molten steel 13 can be exerted uniformly in the circumferential direction.

Further, since the electromagnetic coil 20 is housed in the cooling chamber 10, the cooling water flowing through the cooling chamber 18 cools the mold wall 12 together with the electromagnetic coil 2.
There is an advantage that cooling of 0 can be performed.

FIG. 4 shows another example of the electromagnetic casting mold of the present invention. As shown in FIG.
Is for obtaining a slab having a rectangular cross section, and the mold wall 12, the outer cover 14, the mold retainer 16, and the electromagnetic coil 20 are each formed in a shape corresponding to the shape of the slab. Otherwise, the mold 10 shown in FIG.
Since this is the same as described above, further detailed description is omitted.

The embodiment of the present invention has been described in detail above, but this is merely an example. For example, in the present invention, zirconia, magnesia and other oxides can be used in addition to the above alumina as the metal oxide, and other manufacturing methods other than the upper side may be used as a manufacturing method of the mold wall. The present invention can be configured in various modified forms without departing from the gist of the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a part of a main part of an electromagnetic casting mold according to an embodiment of the present invention, with a part cut away.

FIG. 2 is a sectional view of a main part of the electromagnetic casting mold of FIG.

FIG. 3 is a view showing an example of a method for manufacturing the mold wall of FIGS. 1 and 2.

FIG. 4 is a partially cutaway perspective view showing a main part of an electromagnetic casting mold according to another embodiment of the present invention.

FIG. 5 is an explanatory view of a conventional electromagnetic casting mold and its defects.

[Explanation of symbols]

 10, 40 Mold for electromagnetic casting 12 Mold wall 18 Cooling chamber 20 Electromagnetic coil 28 Conductive part 30 High resistance part 32 Copper alloy plate 34 Powder raw material

Claims (2)

[Claims] (1) A conductive portion made of a conductive metal material and a high-resistance portion which is constituted by including a metal oxide and has a high electric resistance with respect to the conductive portion are alternately arranged in the circumferential direction. And (b) a cooling chamber formed on the outer peripheral side of the mold wall so as to surround the mold wall, and through which a cooling medium is passed. And an electromagnetic coil housed inside the cooling chamber so as to surround the mold wall. 2. The conductive part according to claim 1, wherein the conductive part is made of copper or a copper alloy, and the high-resistance part contains a metal oxide powder and a copper or copper alloy powder of the same kind as the constituent material of the conductive part. A mold for electromagnetic casting, comprising a sintered body of raw powder, wherein the conductive part and the high resistance part are integrated by sintering.